Your post reminds me of the Seinfeld episode where Elaine goes to a Korean nail salon and is convinced the staff is insulting her behind her back in Korean. Elaine then brings George’s dad to the salon (he speaks Korean) where he is reunited with his Korean sweetheart from his Korean War days....hilarious. BTW, they were insulting Elaine, lol.
I’ve had two people tell me that they were being insulted by people speaking another language because those people assumed that the Americans could not understand their native tongue. One was a tall blonde haired blue eyed football player build who is fluent in Spanish. The other was a group of American college students who was eating in an ethnic restaurant in NYC. One of the kids grew up in that country as a missionary kid and was completely fluent in that language.
Both times they confronted the speakers fluently in their native language and it was met with tremendous shock. They thought the stupid Americans couldn’t understand them.